Editing Background check (section)

===Firearms purchases===
{{Further|Gun violence in the United States}}
{{See also|Weapons smuggling}}
In the United States under the [[Gun Control Act of 1968]], citizens and US residents must be 18 years or older to purchase shotguns, rifles, or ammunition. All other firearms – such as handguns – can only be sold to individuals 21 or older. Restricted [[firearm]]s (like [[machine gun]]s), [[suppressor]]s, [[Explosive material|explosives]] or large quantities of precursor [[chemicals]], and [[Concealed carry (USA)|concealed weapons permits]] also require criminal checks.<ref>{{cite web|url=http://fbinicsystem.com/brady-background-check/brady-act-and-nics.html|title=The Brady Gun Background Check Act|last=Davidson|first=Charlie|publisher=Fbinicsystem.com|archive-url=https://web.archive.org/web/20130828071253/http://fbinicsystem.com/brady-background-check/brady-act-and-nics.html|archive-date=28 August 2013|url-status=live|access-date=23 August 2013|date=2009-06-24}}</ref> Checks are also required for those working in positions with special security concerns, such as trucking, [[Port of entry|ports of entry]], and airports (including airline transportation).<ref>{{Cite journal|last=Meng|first=Xiao-Li|date=2012-09-24|title=Enhanced security checks at airports: minimizing time to detection or probability of escape?|journal=Stat|volume=1|issue=1|pages=42–52|doi=10.1002/sta4.6|s2cid=15159478 |issn=2049-1573|url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:10886851|url-access=subscription}}</ref> Laws exist to prevent those who do not pass a criminal check from working in careers involving the elderly, disabled, or children.<ref>{{Cite journal|last=Singh|first=Romila|title=To stay or to leave: Factors that differentiate women currently working in engineering from those who left the profession|journal=Women in STEM Careers|pages=39–56|doi=10.4337/9781781954072.00011|year=2014|isbn=9781781954072}}</ref>